Methods and systems for disinfecting potable water supplies

ABSTRACT

The invention described herein contains two aspects, usable together or separately, that address the needs in the art described above, namely a first aspect that relates to the provision of a transportable water purification system that can be contained on a passenger transport vehicle, and that can use, but does not require, continuous, real-time monitoring, and a second aspect that relates to the use of UV purification of the water as it is uploaded to the passenger transport vehicle after a single pass through the UV chamber.

This application is a continuation-in-part of U.S. Ser. No. 11/048,034,filed Jan. 31, 2005, the entire contents of which are incorporated byreference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to apparatus, methods, and systems for purifying,and maintaining the purity of, water supplies, and in particular potablewater supplies, on transportation equipment, such as planes, trains,ships, and the like. The invention further relates to two aspects: thefirst aspect concerns apparatus, methods, and systems for purifyingwater supplies as they are loaded into the transportation equipment, toensure that the water is supplied in initially purified, desirablypotable, form; the second aspect concerns apparatus, methods, andsystems for treating the water while the transportation equipment is inoperation, maintaining the purified nature of the water for the durationof a trip.

2. Description of Related Art

The issue of water quality, and in particular, of potable water quality,on transportation equipment, such as aircraft, trains, boats and ships,and the like is becoming more of a concern to regulatory authorities.This is particularly true in the United States for commercial passengerairlines with respect to the potable water supplies contained aboardcommercial aircraft.

According to the U.S. Environmental Protection Agency (“EPA” or“Agency”), more than twelve percent of passenger aircraft tested in theUnited States during August and September 2004 “carried water that didnot meet EPA standards.” Water on-board these aircraft tested positivefor total coliform bacteria, with some water also testing positive forE. coli bacteria. As noted by the EPA, “[b]oth total coliform and E.coli are indicators that other disease-causing organisms (pathogens)could be in the water and could potentially affect people's health.” See“Airline Water Supplies” at http://www.epa.gov/airlinewater.

On Nov. 9, 2004, EPA announced commitments from numerous U.S. passengerairlines “to implement new aircraft water testing and disinfectionprotocols.” Administrative agreements executed with these airlinesrequire increased monitoring of water quality on-board commercialaircraft. They also require airlines to analyze possible sources ofcontamination existing outside their aircraft and “to provideinformation related to practices of boarding water from foreign publicwater supplies not regulated by EPA.” See “EPA Reaches Agreement withMajor Airlines to Implement New Aircraft Water Protocols” athttp://yosemite.epa.gov/opa.

Clear from EPA's recent public announcements is that improving waterquality on-board passenger aircraft is an important objective of theAgency. Systems and techniques effecting such improvement thus mayprovide valuable tools to U.S. airlines as they seek to comply with theadministrative agreements. They may also be useful to the EPA as itworks to enhance the quality of drinking and other water made availableto the public.

U.S. Pat. No. 4,871,452 to Kohler, et al., entitled “On-Board WaterSupply,” discloses equipment for purifying waste water from galleys,sinks, and toilets of aircraft. Waste water from these areas dischargesto a tank, after which it passes through a mechanical filter, a bed ofactive carbon, ozone and osmotic stages, and a disinfection stageinvolving addition of chlorine and irradiation with ultraviolet (“UV”)light. Thereafter, the water is made available to aircraft passengersfor certain uses.

Discussed in U.S. Pat. No. 6,143,185 to Tracy, et al. are alternatesystems for decontaminating waste water from aircraft toilets, sinks,and galleys. They too include a mechanical particulate filter, activatedcarbon, and a source of UV light. Alternatively, according to the Tracypatent, the waste water may be exposed to microwaves or treated withchlorine or iodine. A sensor may be used to measure “the level ofclarity of the treated water as an indication of its purity” andrestrict opening of a control valve until acceptable clarity levels areobtained. The entire contents of both the Kohler and Tracy patents areincorporated herein by this reference.

However, these systems and methods are directed at purifying wastewaterremoved from the aircraft. Currently, airlines typically attempt toensure that the potable water aboard the airplanes is fit for humanconsumption by employing a quarterly disinfection protocol and monthlywater sampling. In addition to being time consuming and labor intensive,these techniques may not be sufficient to satisfy the EPA under theagreements described above.

Moreover, quarterly disinfection does not adequately address the issueof contamination introduced in uploaded water, which is of particularconcern for aircraft flying to and from, and being serviced in,non-industrialized areas. In addition, air must be introduced into thewater storage and dispensing system on the aircraft in order to maintainpressurization, as well as to drain the system during routine servicing.This air can introduce pathogens that can multiply, and cause unsanitaryconditions and unacceptable water quality in the intervals betweensamplings or disinfection procedures. In effect, because the waterstorage and dispensing system is routinely exposed to the outsideenvironment, potable water quality cannot be ensured without some formof continuous treatment.

Continuous treatment of potable water supplies presents another set ofpotential problems to be solved, however. Continuous treatment requirescontinuous or semi-continuous dosing of the water, with the requisitedosing equipment (metering and monitoring equipment, dosing agentstorage equipment, and/or equipment for in-situ generation of the dosingagent). Conventional dosing of sanitizing chemicals often requirescontinuous, real-time monitoring is also necessary to ensure adequateperformance.

As a result, there remains a need in the art for an apparatus, method,and system for continuous treatment of portable water supplies topurify, or maintain the purity of the water supplies, that does notrequire continuous real-time monitoring, that is essentiallyself-regulating, and that is easily transportable (e.g., on aircraft),without the need for large or heavy dosing or monitoring equipment.

In addition, in order to reduce the load on such a purification system,and to provide purified water for transportation equipment without sucha purification system, there remains a need in the art for apparatus,methods, and systems capable of purifying water before it is uploaded tothe transportation equipment.

SUMMARY OF THE INVENTION

The invention described herein contains two aspects, usable together orseparately, that address the needs in the art described above, namely afirst aspect that relates to the provision of a transportable waterpurification system that can be contained on a passenger transportvehicle, and a second aspect that relates to the purification of wateras it is uploaded to the passenger transport vehicle.

More particularly, the first aspect of the invention relates to apassenger transport vehicle containing a reservoir with a supply offresh water for use and recirculation on board the transportationequipment, and a water purification device in fluid communication withthe supply of fresh water. The water purification device contains one ormore disinfection chemicals that supply one or more disinfecting speciesto the water by controlled release. This controlled release may take theform of chemical, reduction/oxidation, or electrochemical equilibriumbetween solid disinfection chemical and disinfecting species, or mayoccur over time as a soluble substrate or matrix, in which thedisinfection chemical is embedded, dissolves in the water, or is erodedby the re-circulating water. By controlling the release of thedisinfecting species, the requirement for constant, real-time monitoringof the water chemistry and dosing system is eliminated, although such asystem may be included if desired.

The second aspect of the invention relates to apparatus, methods andsystems for treating water to be uploaded to sanitize it before itbecomes part of the water supply on board the passenger transportvehicle. The apparatus contains a chamber that is in fluid communicationwith a reservoir on the passenger transport vehicle during upload, andhaving an ultraviolet (UV) lamp assembly. The UV lamp assembly isdesirably adapted to emit a dosage of UV radiation above the minimumvalue needed to kill pathogens in the water. By using a UV radiationtreatment system on uploaded water, fast disinfection rates,inactivation of protozoa, disinfection of hard water, and high killrates can be achieved without the generation of disinfection residualsin water. Moreover, this can be achieved by a single pass through thepurification apparatus.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view of a water purification apparatus accordingto the first aspect of the invention.

FIG. 2 is a perspective view of one embodiment of a water purificationapparatus according to the second aspect of the invention.

FIG. 3 is a side plan view of elements of one embodiment of apurification chamber and UV lamp according to the second aspect of theinvention.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Specific embodiments of the first aspect of the invention will bedescribed with respect to FIG. 1. It is to be understood that thisdescription is exemplary and not limitative of this aspect of theinvention, however.

Water purification apparatus 100, shown in FIG. 1, is designed to beincorporated into a passenger transport vehicle, which could be anyknown or future means of transport. These include, without limitation,aircraft, trains, watercraft, automobiles, spacecraft, and the like.Desirably, the passenger transport vehicle is an aircraft. The passengertransport vehicle will contain a water reservoir or storage tank, notshown in FIG. 1, that is in fluid communication with water purificationapparatus 100 through supply line 102 and return line 104. As shown inFIG. 1, water flowing into the apparatus through supply line 102 passesthrough water heater 106. The presence and/or operation of such a heateris optional, but would be desirable in the event that the apparatus isexposed to low temperatures, particularly those at or below the freezingpoint of water. The water heater may be of any suitable type, includinga heat exchanger, an electric heater, a fossil-fuel fired heater, andthe like.

The water then passes through water softening cartridge 108, which cancontain any media suitable for removing at least one type of ion, and inparticular, divalent metal cations, from the water. Suitable mediainclude ion exchange resins, zeolites, and the like. It will beunderstood that the presence and operation of the water softeningcartridge is optional, but would be desirable where the water in thereservoir or storage tank is sufficiently hard that softening is deemednecessary to prevent calcification of water handling equipment.

Water leaving the water-softening cartridge then passes through one ormore disinfection cartridges 110 and/or 112, and returns to the waterreservoir or tank through return line 104. The disinfection cartridgescontain a disinfection chemical that releases disinfecting species intothe water in sufficient concentration to reduce or substantiallyeliminate the presence or growth of undesirable microorganism, includingpathogens such as bacteria and viruses. Moreover, this release occurs ina controlled manner over a period of time, disinfecting the water overthis time period, without the need for continuous dosing or continuousmonitoring, or the requisite equipment. The disinfection cartridgescontain a water inlet, a chamber in fluid communication with the waterinlet, and a water outlet, also in fluid communication with the chamber.Inside the chamber, the water contacts the disinfection chemicalcontained therein, which releases a disinfecting species into the water.The disinfecting species attacks biological contaminants within thewater as it flows out of the outlet of the disinfection cartridge. Thedisinfecting species also react with water to provide extended residualprotection as the water is re-circulated between the water reservoir ortank and the water purification apparatus, and is distributed to itsvarious uses on the passenger transport vehicle.

Suitable disinfection chemicals include, but are not limited to, thosethat are suitable for disinfecting potable water. These can be materialsthat release metal ions into the water, such as Ag(I) ions, Cu(II) ions,and/or Zn(II) ions, including those described in U.S. Pat. Nos.4,608,247; 5,352,369; 5,772,896; 5,855,777; 5,935,609; 6,093,422;6,217,780; and 6,254,894 (the entire contents of each of which areincorporated by reference); and/or available as NATURE2® (Zodiac PoolCare, Inc.). The disinfection chemicals can also be materials thatsupply halogen to the water, such as those described in U.S. Pat. No.5,858,246, or a halogenated polystyrene hydantoin, such as a chlorinepolystyrene hydantoin, commercially available from Vanson Halosource.Yet another alternative is the use of an electrochemical cell togenerate mixed oxidants, including but not limited to hypochlorous acid,from salts dissolved in the water. In this case, the disinfectionchemical is the dissolved salt in the chamber, and the disinfectingspecies is the mixed oxidants produced therefrom.

Each of these systems releases disinfecting species in a controlled orself-regulating manner, wherein the self-regulation mechanism resultsfrom chemical, electrochemical, oxidation/reduction, or otherequilibrium between disinfection chemicals in the chamber and thedisinfecting species in the water.

Returning to FIG. 1, two cartridges containing the disinfectionchemical(s) are shown connected in parallel. When the system containstwo or more cartridges and is operated in a parallel configuration, asshown in FIG. 1, the flow through them can be controlled by a flowcontrol mechanism, such as a flow control mechanism 114, which isoperatively connected to controller 116. As shown in FIG. 1, thisoptional flow controller can also be operatively connected to heater106. It will be appreciated that other control schemes are alsopossible, and fall within the scope of the invention. For example, ifthe system is operated to pass the water through only one of thecartridges at a time, switching to the second cartridge if additionalsanitizing capacity is needed, or if the first cartridge becomes cloggedor the amount of disinfection chemicals therein becomes insufficient, asomewhat different flow control scheme would be used.

In addition to the equipment described above, the water purificationapparatus of the invention can contain other elements, including but notlimited to manifolds, scale inhibition modules, brine cartridges andpumps (for use with electrolytic purification), drain valves,pressurization pumps, water level sensors, and the like, as described inU.S. Ser. No. 11/048,034, incorporated herein by reference.

Specific embodiments of the second aspect of the invention are describedherein by reference to FIG. 2 and FIG. 3, which are exemplaryillustrations and not intended to limit the scope of the claims.

FIG. 2 shows a perspective cutaway view of one embodiment of anapparatus for uploading water to a passenger transport vehicle 200.Water from a nearby source (not shown) enters the apparatus throughinlet 202 and leaves the apparatus through outlet 204 after passingthrough purification chamber 206. While in purification chamber 206, thewater is exposed to UV radiation, which can be monitored by a UV sensor(not shown) disposed adjacent to UV transparent chamber window 208.Power leads 210 and 212 supply electrical current to a UV lamp (notshown) disposed with in the purification chamber 206. Electrical currentis supplied to the leads through electrical connector 214.

FIG. 3 shows a plan view of one embodiment of purification chamber 206.In this embodiment, unpurified water entering the chamber through inlet202 passes through a helical tube 216 and out of the chamber throughoutlet 204. The helical tube 216 coils around a longitudinal core orcentral opening along the length of the chamber, and within which isdisposed UV source 218, shown outside the longitudinal core for clarity,and which is supplied electrical current through leads 212 and 214. Thehelical tube functions to keep the water separate from the UV source,while providing sufficient residence time in the chamber that thedesired dosage of UV radiation is obtained. The tube is relativelytransparent to UV radiation, and is desirably made of quartz or other UVtransparent material. It also optimizes the flow profile of waterthrough the unit, maintaining the intensity of exposure to the UVradiation source

The UV source can be any conventional UV source, but is desirably is aquartz metal halide lamp, such as a quartz medium pressure metal halidelamp. Desirably, the dosage of UV radiation emitted by the UV lamp andtransferred to the water to be treated will be sufficient tosubstantially reduce levels of pathogens such as bacteria, viruses, andprotozoa. It is to be expected that the amount of reduction obtained forbacteria would be larger than that obtained for viruses, which in turnwould be larger than that obtained for protozoa. The dosage of radiationsupplied to the water can be monitored through transparent window 208 bydisposing a suitable UV detector adjacent to the window.

The UV radiation source can be subjected to electrical or electroniccontrol disposed between it and its electrical supply, allowing it tooperate in a periodic or continuous fashion.

The apparatus of this aspect of the invention provides non-chemicaldisinfection without generating a chemical disinfecting residual speciesor disinfecting species by-products, and can disinfect the water passingthrough it in seconds. It can accommodate a wide variety of flow rates.Typical flow rates will generally be above 5 gpm, and will generallyrange from about 5 to 15 gpm, more particularly from about 10-15 gpm.This ability to purify water using flow rates in this range makes theinvention suitable for the uploading of water during the servicing ofpassenger transport vehicles, such as aircraft; However, flow ratesbelow and above this range can also be easily used. The use of theapparatus of the invention results in reduction of pathogens includingbacteria, viruses, and protozoa, with high kill rates, making itparticularly suitable for use in non-industrialized countries, where thequality of available water sources may be less likely to meet U.S. EPAand/or WHO standards for microbiological purity in drinking water, andmay be more likely to be contaminated with such organisms.

It will be apparent that either aspect of the invention can be usedseparately. For example, if it is necessary to upload water from suspectwater sources to transportation equipment without the purificationsystem of the first aspect of the invention, then the second aspect ofthe invention can be used alone. If relatively pure water is availablefor upload, or has been uploaded, then the first aspect of the inventioncan be used to maintain its purity while it is aboard the passengertransport vehicle. Moreover, the aspects can be used together to provideinitially purified water for upload (using the second aspect of theinvention) and maintaining the purity of the water during transport(using the first aspect of the invention).

1.-11. (canceled)
 12. A stand-alone apparatus for purifying water uponupload to a potable water reservoir of an aircraft and configured forinstallation on-board the aircraft, comprising: a. an inlet to receivewater to be purified; b. a purification chamber in fluid communicationwith the inlets and the potable water reservoir of the aircraft, thepurification chamber adapted to receive or hold water from the inlet,comprising a source of ultraviolet radiation disposed within the chamberand capable of irradiating at least a portion of the interior of thechamber and rendering the water potable; c. an outlet to remove purifiedwater from the chamber after a single pass therethrough and to deliverthe potable water to the potable water reservoir of the aircraft; d. anelectrical connector configured to connect to an aircraft powergeneration source; and e. one or more power leads configured to supplypower to the source of ultraviolet radiation in the purificationchamber.
 13. The apparatus of claim 12, wherein the chamber furthercomprises an ultraviolet transparent helical tube between the inlet andoutlet, and a longitudinal core through the helix within which thesource of ultraviolet radiation is disposed.
 14. The apparatus of claim12, wherein the source of ultraviolet radiation comprises a metal halidelamp.
 15. The apparatus of claim 12, wherein the chamber furthercomprises an ultraviolet transparent external window.
 16. The apparatusof claim 15, further comprising an ultraviolet sensor external to thechamber. 17.-21. (canceled)